Crystal structure, conductivity, vibrational, spectroscopic and thermal properties of Rb₃Eu₃[BO₃]₄

The new europium borate Rb3Eu3[BO3](4) is found in the ternary system Rb2O-Eu2O3-B2O3. The Rb3Eu3[BO3](4) powder was fabricated by solid-state synthesis at 750 degrees & Scy; for 40 h and the crystal structure was obtained using by the Rietveld method. Rb3Eu3[BO3](4) crystallizes with the monoclinic K3Er3[BO3](4)-type structure in space group P2(1)/c with unit cell parameters of a = 10.7780 (3), b = 18.0508 (5), c = 14.2213 (5) & Aring;, beta = 111.108 (1)degrees, V = 2581.1 (1) & Aring;(3), Z = 8. DSC and TG measurements indicate that Rb3Eu3[BO3](4) undergoes the solid state decomposition at temperature of 1014 degrees C. The spectral range of transparency for Rb3Eu3[BO3](4) is between 0.35 and 8 mu m and the band gap of E-g similar to 3.77 eV. The electronic structure of Rb3Eu3[BO3](4) was estimated using density functional theory. An IR analysis confirmed the presence of [BO3](3-) groups in Rb3Eu3[BO3](4) crystal structure. At a temperature of 700 degrees C, the ionic conductivity of the title compound reaches 0.510(-3) S/cm (& IEcy;(& acy;) = 0.9 eV).